nika:assert
Core
Tool family from the canonical registry.
invoke
Call this builtin through the invoke verb.
Read this contract
This reference preserves the specification at the revision linked below. Source examples are fragments: their surrounding tasks, inputs and permissions are not supplied here. Consult engine status andnika catalog --tools --json for the installed implementation; a registry declaration is not a runtime qualification.
Usage and behavior
illustration
condition (a CEL ${{ }} boolean) is false · else no-op. The fail-fast guard (distinct from when: which is the skip-guard). condition: uses the canonical ${{ }} CEL surface, never a legacy $task syntax.
Returns true on pass. Throws · NIKA-BUILTIN-ASSERT-001 (assertion failed · tool_error · transient: false · message: lands in the error message · retryable via retry.on_codes, the polling pattern’s lever). A red last assert quarantines writes from that run (out/ moves to .nika/quarantine/<trace>/ in the reference engine — hint assert-quarantine). Keep the assert off the last wave if you need the artifacts from a red run.
Related concepts
Arguments
Pass the values required by the tool contract.
Permissions
Understand authority before granting effects.
Errors and recovery
Read diagnostics and choose a recovery policy.
Workflow templates
Put the fragment inside a complete workflow.
Contract provenance
Read the pinned specification · Canonical registry. Tool identity:nika:assert. Specification revision: f8c5df2127c7.
The Lab language identity is language:tool:assert; the registry view is ecosystem:tool/nika:assert. They refer to this contract without merging their graph identities.